This invention relates to a technique for providing information gained from locating an underground conveyance by electromagnetic signaling.
Many utilities, such as ATandT, bury their pipes and cables (xe2x80x9cutility conveyancesxe2x80x9d) underground both for reasons of safety and esthetics. Underground burial often provides protection to such utility conveyances against weather and other sources of potential damage. Utilities that undertake burial of their conveyances usually make extensive efforts to plot the location of each buried conveyance on a map to facilitate its location in case of repair or replacement. While a map will indicate the general location of a buried conveyance, more precise location information often becomes necessary, particularly in urban environments. For that reason, most utilities that bury their conveyances underground typically rely on electromagnetic signaling techniques to precisely locate such conveyances.
U.S. Pat. No. 5,644,237, issued in the names of Hossein Eslambolchi and John Huffman, on Jul. 1, 1997, and assigned to ATandT, (incorporated by reference herein) discloses an electromagnetic signaling technique for locating a buried utility conveyance. A signal generator applies a locating signal and a confirmation signal to a metallic part of the conveyance. In the case of an optical fiber cable, the metallic part comprises either a metallic sheath or a copper trace wire within the cable. Using a signal detector, a technician detects both the locating signal and the confirmation signal radiated above ground to precisely locate the buried conveyance.
Often, a technician will locate separate portions of the conveyance at different locations along its length. Many of the signal detectors available for detecting conveyance locating signals have the capability of storing certain data collected during a locate operation. Such stored information data allows the technician to gain certain insights about the stored conveyance. Moreover, storing such information may prove useful for later analysis.
Traditionally, the stored conveyance location data, while useful, did not provide an overall representation of the conveyance. Moreover, the location data for each discrete portion of the conveyance provided no ability to facilitate readily combination with the location data associated with other discrete conveyance portions.
Thus, there is a need for a technique that provides location data representative of the entire conveyance.
Briefly, in accordance with a preferred embodiment, the present invention provides location information for a buried conveyance. Initially, location data associated with each of a plurality of discrete conveyance portions is obtained, usually by a technician, who undertakes a locate operation at various spots along the conveyance. The location data for each discrete conveyance portion includes geographic coordinate information, typically obtained by a GPS unit, as to where the location information was obtained. Thereafter, the physical proximity of each discrete conveyance portion is established relative to the other discrete conveyance portions for which location information was obtained. Thereafter, the location data for the discrete conveyance portions is arranged in geographic sequence corresponding to the proximity of the discrete conveyance portions to each other. In this way, the location information associated with each discrete conveyance portion is arranged with the next closest discrete conveyance portion to provide a piece-wise set of location data for display. If desired, the piece-wise locating data can be smoothed using well-known curve filling techniques to yield a continuous function representative of the location data as a function of the conveyance length.